From: ABO blood group and the risk of placental malaria in sub-Saharan Africa
 |  | Primiparae | Multiparae | Total | ||||||
---|---|---|---|---|---|---|---|---|---|---|
 |  | N | OR | 95% CI | N | OR | 95% CI | N | OR § | 95% CI |
Loscertales et al. | Non-O | 38 | Â | Â | 58 | Â | Â | 96 | Â | Â |
 | O-group | 50 | 3.0 | 1.2-7.3 | 52 | 0.8 | 0.3-1.7 | 102 | 1.5 | 0.9-2.7 |
Senga et al. | Non-O | 107 | Â | Â | 221 | Â | Â | 328 | Â | Â |
 | O-group | 96 | 2.2 | 1.1-4.3 | 213 | 0.6 | 0.4-1.0 | 309 | 0.9 | 0.6-1.4 |
Adam et al. | Non-O | 63 | Â | Â | 102 | Â | Â | 165 | Â | Â |
 | O-group | 51 | # | # | 77 | 0.4 | 0.1-1.8 | 128 | 0.3 | 0.1-1.1 |
Present study | Non-O | 34 | Â | Â | 106 | Â | Â | 140 | Â | Â |
 | O-group | 50 | 0.3 | 0.1-1.8 | 188 | 0.7 | 0.3-1.8 | 238 | 0.6 | 0.3-1.3 |